<template>
  <div class="goods">
     <!-- 左侧菜单 -->
    <div class="menu-wrapper" v-el:menu-wrapper >
      <ul>
        <li v-for="item in goods" class="menu-item" :class="{'current':currentIndex===$index}" @click="selectMenu($index,$event)">
          <span class="text border-1px" >
            <span v-show="item.type>0" class="icon" :class="classMap[item.type]"></span>{{ item.name }}
          </span>
        </li>
      </ul>
    </div>
    <!-- 右侧食物 -->
    <div class="foods-wrapper" v-el:foods-wrapper>
      <ul>
        <li v-for="item in goods" class="food-list food-list-hook" >
          <h1 class="title">{{ item.name }}</h1>
          <ul>
            <li @click="selectFood(food, $event)" v-for="food in item.foods" class="food-item bordeer-1px">
              <div class="icon">
                <img width="57" height="57" :src="food.icon">
              </div>
              <div class="content">
                <h2 class="name">{{ food.name }}</h2>
                <p class="desc">{{ food.description }}</p>
                <div class="extra">
                  <span class="count">月售{{ food.sellCount }}份</span>
                  <span>好频率{{ food.rating }}%</span>
                </div>
                <div class="price">
                  <span class="now">￥{{ food.price }}</span>
                  <span class="old" v-show="food.oldPrice">￥{{ food.oldPrice }}</span> 
                </div>
                <div class="cartcontrol-wrapper">
                  <!-- 加减号按钮组件 -->
                  <cartcontrol :food="food"></cartcontrol>
                </div>
              </div>    
            </li>
          </ul>
          
        </li>
      </ul>
    </div> 
    <!-- 购物车组件  传配送费和起送费-->
    <shopcart v-ref:shopcart :select-foods="selectFoods" :delivery-price="seller.deliveryPrice" :min-price="seller.minPrice"></shopcart>
  </div>
  <food :food="selectedFood" v-ref:food></food>
</template>

<script type='text/ecmascript-6'>
  import BScroll from 'better-scroll';
  import shopcart from 'components/shopcart/shopcart';
  import cartcontrol from 'components/cartcontrol/cartcontrol';
  import food from 'components/food/food';
 
  const ERR_OK = 0
  
  export default {

    props:{
      seller:{
        type: Object
      }
    },
    data() {
      return {
        goods:[],
        listHeight: [],
        scrollY: 0,
        selectedFood: {}
      };
    },

    created(){
      this.classMap = ['decrease', 'discount', 'special', 'invoice', 'gurantee'];
      this.$http.get('api/goods/').then((response) => {
          response =response.body
          if(response.errno === ERR_OK){

            this.goods =response.data;

            this.$nextTick(() => {
              this._initScroll();
              this._calculateHeight();
            
            });

          }
      })
    },
    computed: {
      currentIndex() {
        for(let i=0;i<this.listHeight.length; i++){
          let height1 = this.listHeight[i];
          let height2 = this.listHeight[i + 1];
      
          if (!height2 || (this.scrollY >= height1 && this.scrollY < height2)) {
            return i;
          }
        }
        return 0;
      },
      selectFoods() {
        let foods = [];
        this.goods.forEach((good)=>{
          good.foods.forEach((food)=>{
            if (food.count) {
              foods.push(food);  
            }
          });
        });
        return foods;
      }
    },
    methods: {
      selectMenu(index,event) {
        
        if(!event._constructed){
          return;
        }
        let foodList = this.$els.foodsWrapper.getElementsByClassName('food-list-hook');
        let el = foodList[index];
        this.foodsScroll.scrollToElement(el, 300);
      },
     _drop(target){
       //体验优化，异步执行小球下落
       this.$nextTick(() => {
        //访问子组件
        this.$refs.shopcart.drop(target);
       })
      },
      _initScroll() {
        this.menuSrcoll =new BScroll(this.$els.menuWrapper, {
          //按钮可以点击
          click: true
        });
        this.foodsScroll =new BScroll(this.$els.foodsWrapper, {
          // 监听实时滚动
          click: true,
          probeType: 3
        });
        //拿到scroll值
        this.foodsScroll.on('scroll', (pos)=>{
          this.scrollY =Math.abs(Math.round(pos.y));
        })
      },
      // 计算食品列高度
      _calculateHeight() {
        let foodList = this.$els.foodsWrapper.getElementsByClassName('food-list-hook');
        let height = 0;
        this.listHeight.push(height);
        
        for(let i=0; i< foodList.length; i++) {
          let item =foodList[i];
          height += item.clientHeight;
          this.listHeight.push(height);
        }
      },
      selectFood(food, event){
        if (!event._constructed) {
          return;
        }
        this.selectedFood = food;
        this.$refs.food.show();
      }
    },
    components: {
      shopcart,
      cartcontrol,
      food
    },
    // 接受子组件传来的事件
    events: {
      'cart.add'(target) {
        this._drop(target);
      }
    }
  }
</script>

<style lang='stylus' rel='stylesheet/stylus'>
  @import "../../common/stylus/mixin";
  .goods
    display: flex 
    position: absolute
    top: 174px
    bottom: 46px
    width: 100%
    overflow: hidden
    .menu-wrapper
      flex: 0 0 80px
      width: 80px
      background : #f3f5f7
      .menu-item
        display: table
        height: 56px
        width: 56px
        padding: 0 12px
        line-height: 14px
        &.current
          position: relative
          z-index: 10
          margin-top: -1px
          background: #fff
          font-weight: 700
          .text
            border-none()
        .icon
          display:inline-block
          width: 16px
          height: 16px
          vertical-align:top
          margin-right: 2px
          background-size: 16px 16px
          background-repeat: no-repeat
          &.decrease
            bg-image('decrease_3')
          &.discount    
            bg-image('discount_3') 
          &.guarantee
            bg-image('guarantee_3')
          &.invoice
            bg-image('invoice_3')
          &.special
            bg-image('special_3')
        .text
          display: table-cell
          width: 56px
          vertical-align: middle
          border-1px(rgba(7 ,17, 27, 0.1))
          font-size: 12px         
    .foods-wrapper
      flex: 1
      .title
        padding-left: 14px
        height: 26px
        line-height: 26px
        border-left:2px solid #d9dde1
        font-size: 12px
        color:rgb(123,153,159)
        background #f3f5ff
      .food-item
        display:flex
        margin: 18px
        padding-bottom:8px
        border-1px(rgba(7 ,17, 27, 0.1))
        &:last-child
          border-none()
          margin-bottom: 0
        .icon
          flex:0 0 57px
          margin-right:10px
        .content
          flex:1
          .name
            margin:2px 0 8px 0
            height: 14px
            line-height:14px
            font-size:14px
            color: rgb(7,17,27)
          .desc, .extra
            line-height: 10px
            font-size: 10px
            color: rgb(147, 153, 159)
          .desc 
            line-height: 12px
            margin-bottom: 8px
          .extra
            &.count
              margin-right: 12px   
          .price
            font-weight: 700
            line-height: 24px
            .now
              margin-right: 8px
              font-size: 14px
              color: rgb(240, 20, 20)
            .old
              text-decoration: line-through
              font-size: 10px
              color: rgb(147, 153, 159)
          .cartcontrol-wrapper
            position absolute
            right -12px
            bottom 12px
</style>